CN102325970A

CN102325970A - Particulate filter

Info

Publication number: CN102325970A
Application number: CN2010800095548A
Authority: CN
Inventors: D·M·比尔; A·K·海贝尔; P·坦登
Original assignee: Corning Inc
Current assignee: Corning Inc
Priority date: 2009-01-21
Filing date: 2010-01-21
Publication date: 2012-01-18
Anticipated expiration: 2030-01-21
Also published as: WO2010093504A1; JP2012515648A; JP2015128765A; CN102325970B; PL2389502T3; EP2389502B1; EP2389502A1; US8231701B2; JP2014167294A; US20100180772A1

Abstract

A kind of particulate filter [100] can comprise entry end [102], outlet end [104] and a plurality of passage [108; 110]; Said a plurality of passage setting also is configured such that fluid flows from entry end [102] towards outlet end [104]; Said passage [108,110] is used for the porous wall [106] of capturing particulates material structure and limits.The cell densities of said porous wall [106] is approximately less than 200cpsi, and wall thickness is approximately less than 14 mils, and mean pore sizes is about the 13-20 micron, and overall porosity is approximately greater than 45%, and pore-size distribution makes less than 10 microns hole contribution approximately less than 10% porosity ratio.

Description

Particulate filter

The cross reference of related application

The preference that No. the 12/356th, 965, the U. S. application that the application requires to submit on January 21st, 2009, its content is through with reference to being incorporated into this.

Technical field

The present invention relates generally to particulate filter, and the regeneration method of particulate filter.More particularly, the particulate filter that the present invention relates to be used for capturing the particulate that contains in the engine exhaust and make said particle burning, for example wall-flow type particulate filter.

Background technique

The problem of environment aspect impels the much local people in the whole world that the discharging of internal-combustion engine is claimed.Many pollutants that people use catalytic converter to remove to comprise in the waste gas; But people often need use filter to remove particulate matter, for example ash and soot.For example, people use the wall-flow type particulate filter to remove particulate from waste gas in the engine system of being everlasting.These particulate filters can be used the honeycomb substrates manufacturing, comprise the parallel flow channel or the duct of separating with inner porous wall.The entry end of flow channel and outlet end can optionally stop up, and for example stop up with tessellated form, force waste gas after getting into base material, through said inner porous wall, thereby make said porous wall hold back a part of particulate in the waste gas.The particulate of porous wall is captured and can be carried out two different stages:, on the porous wall of flow channel, capture (filtration of cake bed) then at first at porous wall captured inside (deep-bed filtration).

In this way, it is found that the wall-flow type particulate filter can remove particulate, for example ash and soot effectively from waste gas.But along with the increase of the amount of the particulate of capturing in porous wall and the passage, the pressure drop on the said wall-flow type particulate filter increases.(for example there are not enough grieshoch for unadjusted filter; Be used for stoping particulate matter to see through said porous filtering wall); The rising of pressure drop fast (usually less than 1 grams per liter (g/L)) can take place usually in the initial deep-bed filtration stage; At cake bed filtration stage, along with the loading of particulate, pressure drop raises gradually then.The back pressure that the pressure drop meeting of said rising causes imposing on motor increases gradually, correspondingly reduces the performance of motor.Therefore, before the level that is cumulative too high, soot is carried out oxidation usually, be removed with controlled reclaiming process.

For example, a kind of regeneration techniques of routine comprises the waste heating that gets into to certain temperature, this temperature support is burnt soot from filter process.But this kind method also can release energy with the mode of heat energy, can make the temperature of filter raise.If the soot level in the filter is too high, regeneration can make the temperature of filter be elevated to the degree that causes fault, can cause the heat of filter to cause crackle or fusing.The fault of filter may cause the filter efficiency of filter seriously to reduce, and needs the replacement filter.Therefore, for fear of the high-pass filter temperature that may cause the filter fault, preferably regenerate in the horizontal situation of enough low soot.

But people also hope to avoid under low excessively soot level, to trigger regeneration, and this is because can cause irrational a large amount of regenerative operation like this.The regenerative operation that repeats may cause following adverse effect, for example causes the oil dilution, disadvantageous NO _x, fuel aspect unfavorable, and/or engine power loss.Therefore possibly hope that bigger interval is arranged between twice regenerative operation, guarantee before the soot level reaches critical soot level, to trigger regeneration simultaneously, under the high-pass filter temperature, regenerate avoiding.

For example, can come the soot level in the monitor filter, when the amount of soot reaches critical limit, trigger regeneration with the pressure drop on the wall-flow type particulate filter.But; In fact there are some uncertainties in the actual soot level in the filter; This is because there is the influence of following factor; For example: measurement error, in the different filters to the variation of pressure drop response, and/or the variation that takes place along with the existence of ash in the filter of pressure drop response (for example filter is new or has comprised the ash (ash is regulated) of accumulation).For those for the loading of the soot in the cake bed filtration stage has the filter that responds than low pressure loss (slope that for example pressure drop-soot loads level curve is more shallow), this uncertainty possibly be sizable.But; From the purpose that improves fuel efficiency; Some conventional methods are primarily focused on regardless of the particulate load condition; Reduce the pressure drop on the filter as far as possible, thereby cause not only the response of low pressure drop to the soot loading being arranged, and this situation is also arranged at cake bed filtration stage in the initial deep-bed filtration stage.

But the pressure drop response that keeps low also can cause adverse influence to the Economy of fuel.More particularly,, load the low pressure drop response that increases, particularly when utilizing pressure drop to trigger regenerative operation, may cause negative effect fuel efficiency to soot at cake bed filtration stage.Regeneration need be to system's intake, and the temperature of the feasible gas that gets into is elevated to sufficiently high level, to cause the burning of soot.This energy input is derived from the back injection of fuel usually, but no matter takes which kind of energy input devices, all can cause the loss of fuel economy.

Therefore; People need provide a kind of filter; It shows during cake bed filtration stage particulate matter is loaded higher pressure drop response (slope that is pressure drop-soot loading level curve is steeper); While (for example when filter is cleaning) before particulate matter loads shows low pressure drop, and in the deep-bed filtration stage particulate matter load table is revealed lower pressure drop response (being that pressure drop-soot loading level curve has more shallow slope).It would also be desirable to provide a kind of filter, make it can realize high filtration efficiency (FE).Therefore, possibly be desirable to provide some filters, it has the geometric properties and the microstructure character that can realize above-mentioned required characteristic.

It would also be desirable to provide a kind of filter regeneration technology, it can not trigger regeneration (thereby causing too frequent regeneration) prematurely, guarantees simultaneously before filter reaches critical particulate matter loading level, to regenerate.In other words, be desirable to provide a kind of filter and regeneration techniques, compare with the routine techniques that is used for triggering regeneration, it can be more near triggering regeneration under the particulate matter loading level of critical loading level.

Summary of the invention

The present invention can solve above-mentioned one or more problem, and/or can show one or more required characteristics mentioned above.Through following description, can be expressly understood that other characteristic and/or advantage.

According to various exemplary mode of executions, the invention provides a kind of particulate filter, it comprises entry end; Outlet end, and a plurality of passage, said passage setting also is configured such that fluid flows from said entry end towards outlet end; Said passage is used for the porous wall of capturing particulates material structure and limits; The cell densities of said porous wall is approximately less than 200cpsi, and wall thickness is approximately less than 14 mils, and mean pore sizes is about the 13-20 micron; Overall porosity is approximately greater than 45%, and pore-size distribution makes less than 10 microns hole contribution approximately less than 10% porosity ratio.

According to various other illustrative embodiments; The invention provides a kind of particulate filter; It comprises entry end, outlet end, and a plurality of passage, and said passage setting also is configured such that fluid flows from said entry end towards outlet end; Said passage is used for the porous wall of capturing particulates material structure and limits, and it is that 500 ℃, rate of flow of fluid are 1400 meters that said particulate filter is configured such that in temperature ³/ hour condition under flow through said particulate filter fluid have from said entry end to outlet end and be less than or equal to 1.7 kPas low cleaning pressure drop; In the deep-bed filtration stage particulate of particulate filter is loaded and to have low pressure drop response; Be slope be less than or equal to approximately 3.4 kPas/(grams per liter soot density); At cake bed filtration stage the particulate of particulate filter is loaded and to have steep pressure drop response, promptly slope approximately greater than 0.9 kPa/(grams per liter soot density).

Other purpose and advantage will be in description subsequently partly statement, and be in part apparent according to this description, maybe can understand through implementing following each side.These purposes and advantage will are familiar with and obtain to key element through particularly pointing out in the accompanying claims with combination.

The generality description and the following detailed description that should be understood that the front all are example and illustrative, do not constitute the restriction to claims.

Brief Description Of Drawings

Can be separately through following detailed description or through following detailed description and combine accompanying drawing to understand the present invention.The accompanying drawing that comprises provides further understanding of the present invention, and accompanying drawing is bonded in this specification and constitutes the part of specification.Accompanying drawing has shown one or more exemplary mode of executions, is used for explaining various principles and operation with describing.

Fig. 1 is the perspective view of an illustrative embodiments of particulate filter of the present invention;

Fig. 2 is the schematic cross-section of the particulate filter of Fig. 1;

Fig. 3 A is that the pressure drop-particulate of the particulate filter of the various illustrative embodiments according to the present invention loads graph of a relation;

Fig. 3 B is a cake bed filtration stage, and to the steeper pressure drop response diagram of soot loading of particulate filter, and at cake bed filtration stage, the lower pressure drop response diagram of soot loading to particulate filter compares the two;

Fig. 4 shows that for the filter of cleaning and the filter that has loaded soot, pressure drop is along with the analog data result of pit canal variable density relation;

Fig. 5 has shown that for the filter with various pit canal density pressure drop loads the analog data result of variation relation along with soot;

Fig. 6 has shown that for the filter with all lengths pressure drop loads the analog data result of variation relation along with soot;

Fig. 7 A, 7B and 7C have shown that for the filter with various wall thickness pressure drop loads the analog data result of variation relation along with soot;

Fig. 8 A has shown that for the filter with various geometrical constructioies the cleaning pressure drop is along with the analog data result of the variation relation of wall mean pore sizes;

Fig. 8 B has shown that for the filter with various geometrical constructioies the cleaning pressure drop is along with the experiment test result of the variation relation of wall mean pore sizes;

Fig. 9 A has shown that for the filter with various geometrical constructioies the cleaning pressure drop is along with the analog data result of the variation relation of wall pore rate;

Fig. 9 B has shown that for the filter with various geometrical constructioies the cleaning pressure drop is along with the experiment test result of the variation relation of wall pore rate;

Figure 10 A has shown the analog data result of cleaning and filtering efficient along with the variation relation of wall mean pore sizes;

Figure 10 B has shown the experiment test result of cleaning and filtering efficient along with wall mean pore sizes variation relation;

Figure 11 A has shown the analog data result of cleaning and filtering efficient along with wall pore rate variation relation;

Figure 11 B has shown the experiment test result of cleaning and filtering efficient along with wall pore rate variation relation;

Figure 12 has shown that the wall pore rate is to because the analog data result of the influence of the initial back pressure pressure drop slope that deep-bed filtration causes;

Figure 13 has shown that cinclides directly distributes to because the analog data result of the influence of the initial back pressure pressure drop slope that causes of deep-bed filtration.

Preferred implementation details

As indicated above; The pressure drop that loads for soot when use responds the soot loading level of monitor filter, and when the soot heap(ed) capacity reaches critical limit, triggers when regenerating; Because following factor; There are some uncertainties in soot loading level actual in the filter: measurement error, and the variation of pressure drop response in the different filters, and pressure drop responds the variation that takes place along with the ash that exists in the filter.Because these uncertainties trigger regeneration through regular meeting under the corresponding situation of soot loading level less than critical soot loading level of pressure drop.In some conventional filter configurations; With cake bed filtration stage soot being loaded the situation with higher pressure drop response compares; When at cake bed filtration stage, filter loads when having lower pressure drop response soot, and said uncertain can making need earlier be triggered regenerative operation.

The present invention has imagined and is configured to remove the particulate filter of particulate matter from fluid stream, and is used for method that said particulate filter is regenerated.More particularly, said particulate filter can be configured to be used for the capturing particulates material, soot that for example comprises in the engine exhaust and ash.The present invention has considered some particulate filters, and it has low pressure drop under the state of cleaning, and when filter is dirty, has high pressure drop, so-called dirty that is to say, and filter has loaded and has comprised the for example particulate matter of soot.In other words; Various exemplary mode of execution of the present invention has been considered the particulate filter configuration; Said configuration is under initial situation; (for example under the situation of cleaning) has low pressure drop before accumulation ash and soot, has lower pressure drop response (starting stage of for example capturing ash and soot within the wall at filter has minimized slope) in the deep-bed filtration stage, but very sensitive to the soot accumulation that continues; The increase that cake bed filtration stage filter soot is loaded has steeper pressure drop response (for example on filter wall, capture the remaining stage of soot, have maximized slope).In an exemplary mode of execution, the pressure drop in the deep-bed filtration stage responds the pressure drop response near cake bed filtration stage.In other words, at deep-bed filtration and cake bed filtration stage, the slope of pressure drop-soot loading curve is basic identical.

For example; The microstructure character of the filter that various illustrative embodiments according to the present invention are measured; For example aperture, porosity ratio and/or pore-size distribution possibly be enough to the cleaning pressure drop that on filter, provides low, and in the deep-bed filtration stage, filter loads soot has low pressure drop response.In addition; The geometric properties of the filter that various other illustrative embodiments according to the present invention are measured, for example cell densities (promptly per square inch duct number (cpsi)), wall thickness, filter length and/or filter diameter possibly be enough at cake bed filtration stage the soot of filter loaded the pressure drop response that provides steep.

Illustrative embodiments mentioned above and as herein described has shown some particulate filters; Its geometrical construction and microstructure can produce low cleaning pressure drop; In the deep-bed filtration stage (if any) particulate of particulate filter is loaded and to have low pressure drop response, at cake bed filtration stage the particulate load table of particulate filter is revealed steep pressure drop response, thereby promote the Economy of motor fuel; Reduce the filter regeneration frequency, improve the filter efficiency of filter.

In this article, term " particulate filter " or " filter " are represented a kind of structure, and it can remove particulate matter from the fluid stream through said structure.The present invention can be used for removing particulate matter arbitrarily from the stream of fluid arbitrarily, and said fluid stream can be the form of gas or liquid.Gas or liquid also can comprise other phase, for example the solid particle in gas or flow of liquid, the perhaps drop in gas stream.Non-restrictive illustrative fluid stream comprises the waste gas that internal-combustion engine produces, for example DENG and petrol engine, aqueous liquid stream, the coal combustion flue gas that coal gasifying process produces.

Said particulate matter can be phase arbitrarily.Therefore, solid or liquid that said particulate matter can be used as in gaseous fluid stream exist, and perhaps exist as the solid in liquid fluid stream.Exemplary particulate matter comprises for example diesel engine microparticle matter (for example by the particulate constituent in the diesel exhaust of diesel car and truck discharging), and it comprises diesel oil soot and aerosol, for example grey particulate, galling particle, sulphate and/or silicate.In this article, term " soot " is illustrated in the combustion process, because the impurity carbon granule that the partial combustion of hydro carbons produces.The non-flammable metallic material that term " ash " expression is almost found in all petroleum productss.For diesel applications, ash is usually produced by crankcase oil and/or the catalyzer that is derived from fuel.In this article; Term " critical particulate loading level " expression has the particulate loading level of following characteristic: in the case; The obstacle of pressure drop is too high; Make motor to operate, high temperature and/or big heat gradient when perhaps regenerative operation possibly burn owing to particulate matter cause fault to filter.

Particulate filter of the present invention possibly have arbitrary shape or the geometrical construction that is suitable for the particulate application; And various configurations and design, include but not limited to for example wall-flow type integrated structure or part flow type integrated structure (being the combination in any of wall-flow type integrated structure and flow type integrated structure).Exemplary wall-flow type single piece comprises for example any integrated structure; It comprises passage or porous network or other path; Wherein in the opposite end of structure; Independently path opens wide and stops up, thus at fluid when an end flows to the other end, promote fluid flow to cross unitarily formed conduit wall.Exemplary part flow type single piece comprises the structure of integrated arbitrarily that for example has following character: this structure is as indicated above to be the partial wall-flow formula; Be the part flow type simultaneously; The passage of a part or porous network or other path all are open at two ends, allow fluid stream to flow through said unitarily formed path from an end to opposite end.Each exemplary mode of execution of the present invention has considered to adopt the porous geometrical construction of honeycomb ceramics configuration, and this is because this kind structure per unit volume has high surface area, can be used for the deposited particles material.Those of ordinary skills can understand, and in fact the cross section in the duct of honeycomb body structure can have shape arbitrarily, are not limited only to square or Hexagon.Similarly, can further understand through following description, honeycomb body structure can be configured to wall-flow type structure or part flow through structure.

Fig. 1 shows and is fit to be used for the illustrative embodiments of particulate filter of embodiment of the present invention.A plurality of path 10s 8,110 that said particulate filter 100 has entry end 102, outlet end 104 and extends to outlet end 104 from said entry end 102.Said path 10 8,110 is limited the porous wall 106 that intersects, thereby forms the configuration that is the honeycomb ceramics shape substantially.Although showing the channel cross-section (promptly on the plane perpendicular to filter 100 longitudinal axis) of particulate filter 100 among the figure is square basically; But those of ordinary skills can understand; Path 10 8; 110 can have various other geometrical constructioies, and for example cross section is circle, square, triangle, rectangle, Hexagon, sinusoidal or its combination in any, and can not deviate from scope of the present invention.

In addition; Although show that particulate filter 100 is cylindrical, it will be appreciated by those skilled in the art that this kind shape only is exemplary; Particulate filter of the present invention can have different shape, includes but not limited to ellipse, bulk, cube shaped, triangle etc.

Said particulate filter 100 can be processed by the material of any appropriate, and said porous wall 106 is not limited to the porous material of any specific.Exemplary material comprises various porous ceramics, includes, but are not limited to steinheilite, silicon carbide, silicon nitride, aluminium titanates, reason nepheline, calcium aluminate, basic zirconium phosphate and spodumene.In various illustrative embodiments, said particulate filter 100 can be through for example extruding and/or moulding formation integrated structure.Those of ordinary skills are familiar with being used for forming the various technology of said ceramic integral type structure.The particulate filter of various illustrative embodiments also comprises crust, forms the outer circumferential side surface of filter.Said crust can be by the material manufacture identical or different with porous wall, and in various mode of executions, its thickness can be greater than porous wall.

As depicted in figs. 1 and 2; Each illustrative embodiments of the present invention has also been considered a kind of particulate filter 100; It has the channel end that one or more selectivity are stopped up, thereby the wall-flow type structure is provided, and this kind structure makes and more closely contacts between fluid stream and the porous wall 106.Fig. 2 is the schematic cross-section that the particulate filter 100 of Fig. 1 obtains along straight line 2-2, has shown the path 10 8,110 in the particulate filter 100 among the figure.Path 10 8 alternately and 110 seals with stopping up piece 112 in opposite end.For example, in the illustrative embodiments of Fig. 1 and Fig. 2, passage 110 stops up piece 112 sealings in entry end 102 usefulness of filter 100, and path 10 8 stops up piece 112 sealings in outlet end 104 usefulness of filter 100.The sealing of said path 10 8,110 forces fluid convection to pass through porous wall 106.Fluid through entry end 102, flows into particulate filter 100 via path 10 8 along direction arrow F, and chock 112 sealings are blocked at passage middle outlet end 104 places.This kind is enclosed in the path 10 8 interior build-up of pressure accumulations of sealing, forces fluid to pass through the porous wall 106 of path 10 8.When forced fluid through porous wall 106 time, particulate matter is captured in the wall 106, and fluid then passes through in the clear.Fluid after filtering then gets into adjacent passage 110, via outlet end 104, leaves particulate filter 100 through passage 110.

Said obstruction piece 112 can be processed by the material of any appropriate, is not limited to any specific obstruction thickener or material.In various illustrative embodiments, for example specifically in the filter of being made by steinheilite, said obstruction piece 112 can be formed by the steinheilite grog that uses with Bond and filler.For example; Exemplary obstruction piece can also comprise the obstruction thickener of being made up of the mixture of following component: aluminium titanates powder, calcium aluminate powder, Kaowool

aluminosilicate fibre, silicon dioxide gel, methyl cellulose binder and water make its curing through heating.

According to various exemplary mode of executions of the present invention, said porous wall 106 can for example be trapped in particulate matter within the thickness of porous wall 106, and be trapped on the surface 107 of porous wall 106 with various mode capturing particulates material.The process that particulate matter is trapped within the filter wall is commonly referred to as deep-bed filtration.But when surpassing a certain degree, the deposition of the particulate matter in the porous wall 106 can reduce the breathability of wall fully, makes subsequently particulate matter be trapped on the surface 107 of porous wall 106 and takes place.This kind captured and often is known as the filtration of cake bed.In the deep-bed filtration stage, along with the soot loading of particulate filter, steep increase takes place in back pressure.Therefore, hope that loading has low pressure drop response (for example reducing the slope of pressure drop response curve as far as possible) to particulate matter in the deep-bed filtration stage.Because the particulate matter of deposition itself is also observed filter efficiency and is increased to maximum filtering efficient from initial (cleaning and filtering) filter efficiency as filter medium.Compare with deep-bed filtration, at cake bed filtration stage, increased efficiency farthest, back pressure is along with the increase that soot loads more relaxes (the pressure drop response that for example loads to soot is less usually).

Therefore, compare with cake bed filtration stage, bigger usually at the particulate filter in deep-bed filtration stage to the pressure drop response that particulate matter loads, therefore in the pressure drop response curve 200 of filter, form crooked 202 (shown in Fig. 3 A).In order to reduce the slope variation of pressure drop response curve 200 as far as possible at crooked 202 places; Various illustrative embodiments of the present invention considered the starting stage of deep-bed filtration reduce the pressure drop response curve slope (promptly with the deep-bed filtration stage usually observed higher slope compare; More shallow slope is provided), with near after the slope (seeing Fig. 3 A) of pressure drop response curve of cake bed filtration stage.In order to eliminate and/or at utmost to reduce initial bending 202 (for example provide and have the basic curve 200 of slope continuously); Various other illustrative embodiments are also considered a kind of particulate filter is constructed (for example based on its microstructure); Thereby eliminate or at utmost reduce deep-bed filtration, the particulate of this filter loads and directly causes the cake bed to filter.But in the case, the present invention has still considered some filters, and these filter configurations become to have low cleaning pressure drop, at cake bed filtration stage particulate is loaded to have steep pressure drop response.

Those of ordinary skills can understand, and the pattern of the channel end of obstruction illustrated in figures 1 and 2 and mentioned above only is exemplary, can under the prerequisite that does not deviate from the scope of the invention, adopt the layout of other blocking channel.In addition, those of ordinary skills can understand, and can also under the prerequisite that does not deviate from the scope of the invention, use part flow type filtration device structure (portion of channel that is filter is blocked, and some passages of filter all are open at two ends).More than the description of filtering about deep-bed filtration and cake bed; And about the description of the pressure drop of these filtration stages response; Can be used for part flow type filtration device structure with wall-flow filter structural equivalence ground; This is because at least a portion fluid that flows through passage in the part flow through structure through the porous filtering wall, makes particulate matter be captured within these walls.

As indicated above, said particulate filter, the geometrical construction of particulate filter 100 as depicted in figs. 1 and 2 and porous wall constitutive property can influence the fuel economy of motor, the filter efficiency of particulate filter, and the regeneration frequency of particulate filter.To describe in more detail hereinafter; The inventor finds; Have low cleaning pressure drop and particulate is loaded the particulate filter that (for example at cake bed filtration stage) have a steep pressure drop response and can promote fuel economy and filter efficiency, reduce the frequency of filter regeneration simultaneously.In addition; The inventor finds; The combination of particulate filter geometrical construction and porous wall constitutive property can realize high exhibits initial filtration efficiency; Low cleaning pressure drop loads low pressure drop response in the deep-bed filtration stage (if any) to particulate, and at cake bed filtration stage particulate is loaded steep pressure drop response.

In this article, term " cleaning pressure drop " expression when particulate filter be when cleaning, fluid is from the pressure drop of entry end when outlet end flows through particulate filter.Therefore, have the filter that the particulate filter of " low cleaning pressure drop " representes to have following character: it can allow fluid relatively freely to pass through in initial, when fluid is through filter, obtains low pressure drop.In this article, term " the pressure drop response that particulate is loaded " expression when filter dirty, when having loaded particulate matter, when fluid from entry end when outlet end flows through said particulate filter, the change in pressure drop of the fluid that causes.In this article; Term " the low pressure loss response in the deep-bed filtration stage to the particulate loading of particulate filter " a kind of filter of expression reduces (comparing with the conventional filtration device) in the starting stage of deep-bed filtration to the receptance that particulate loads; Make in particulate filter to load in the particulate matter that the pressure drop of the fluid through this filter increases relatively low (comparing with the conventional filtration device).In this article; Term " in the steep pressure drop response that cake bed filtration stage loads the particulate of particulate filter " a kind of filter of expression after the receptance rising (comparing) that particulate is loaded of cake bed filtration stage with the conventional filtration device; Make in particulate filter to load in the particulate matter that the pressure drop of the fluid through this filter increases relatively large (comparing with the conventional filtration device).

Fig. 3 A has shown the schematic representation according to the pressure drop response that in the particulate filter of the present invention particulate is loaded.Shown in Fig. 3 A; The filter of various illustrative embodiments can have low cleaning pressure drop (for example working as filter cleans) according to the present invention; Note does 204; Loading has lower (or shallow) pressure drop response (the initial very short particulate loading procedure that for example curve 200 is represented up to crooked 202 places in Fig. 3 A) to particulate in the deep-bed filtration stage; Note does 206, at cake bed filtration stage particulate is loaded and have steeper pressure drop response (for example in the particulate loading procedure that the linear segment of Fig. 3 A curve shows), and note does 208.

Shown in Fig. 3 A; Those of ordinary skills can understand; Although the slope of 206 parts in expression deep-bed filtration stage is greater than the slope of the cake bed filtration stage of note work 208 in the curve in the curve; But compare with the filtration device structure of routine, the pressure drop response curve of illustrative embodiments of the present invention has more shallow slope in the deep-bed filtration stage, has steeper slope at cake bed filtration stage.

Referring to Fig. 3 B; Curve 300 has shown that particulate filter (for example has more shallow pressure drop response to the pressure drop response that soot loads at cake bed filtration stage; The conventional filtration device), curve 302 has shown the particulate filter that has steeper pressure drop response at cake bed filtration stage.If representing the curve 300 of shallow pressure drop response to be extrapolated to soot loading level is zero, then have lower cleaning pressure drop, and have lower soot loading pressure drop at cake bed filtration stage, obtain shallow generally response slope to the soot loading.If will be extrapolated to soot loading level corresponding to the curve 302 of steep pressure drop response is zero, then has lower cleaning pressure drop, and soot is loaded steep response slope at cake bed filtration stage.In Fig. 3 B, critical soot is loaded level, that is to say for fear of filter temperature in regenerative process to be elevated to unacceptable level, the soot loading level that therefore can not surpass, note is made SL _c

As discussed above, compare with the soot loading of reality, predict that through the pressure drop on the monitoring particulate filter there is certain uncertainty in the soot loading.As discussed above, various factors, the for example variation of the pressure drop of given filter response, the level of the ash that exists in the filter, and/or be used for the accuracy of the sensor of this calculating all can be made contributions to this kind uncertainty.Therefore, probabilistic scope of pressure drop shows with bracket 304 on the pressure drop axle of Fig. 3 B.

For fear of surpassing SL _c, after-treatment system uses the lower limit of pressure drop uncertain region to trigger regeneration usually.In Fig. 3 B, the lower limit of this uncertain region is corresponding to soot loaded targets value (SL _t), have enough confidence coefficients to show this moment, considering under probabilistic situation, do not surpass SL as yet _c, trigger regeneration at this moment.Shown in Fig. 3 B, the SL of steep pressure drop response curve _t(SL _{T is steep}) considerably beyond the SL of shallow pressure drop response curve _t(SL _{T is shallow}).Therefore, has identical SL at two kinds of filters _cSituation under; With at cake bed filtration stage soot is loaded the particulate filter with shallow pressure drop response and compares, cake bed filtration stage have the regeneration (curve 302 expressions) of the particulate filter of steep pressure drop response can be with regenerative operation between long blanking time carry out.

As discussed above; The present invention has considered the particulate filter that structure has various geometric propertieses and porous wall microstructure character; Thereby realize that the required particulate (for example soot) of filter the loading at cake bed filtration stage has steep pressure drop response; Simultaneously when filter is for cleaning, keep low pressure drop and high filter efficiency.In certain exemplary embodiments, the present invention has also considered a kind of particulate filter configuration, and deep-bed filtration seldom wherein takes place, and deep-bed filtration does not perhaps take place, and particulate loads and directly causes the cake bed to filter basically.But in other illustrative embodiments, the present invention has also considered a kind of particulate filter of structure, and deep-bed filtration wherein takes place, and realizes the low pressure drop response that particulate is loaded in the deep-bed filtration stage.

Scope for the variable (for example geometric properties and porous wall microstructure character) of confirming filter design; To realize required high-pass filter FE; Low cleaning pressure drop; The low pressure loss response that particulate (for example soot) is loaded in the deep-bed filtration stage (if any), and in the steep pressure drop response of cake bed filtration stage to particulate (for example soot) loading, the inventor uses analog data and the experimental result that shows and describe below in conjunction with Fig. 4-13.

Pressure drop (unit is the inch of mercury, inch Hg) after Fig. 4 has shown the cleaning pressure drop and loaded soot is along with the analog data of the variation relation of the cell densities (unit is duct/square inch (cpsi)) of filter porous wall.In Fig. 4, be 55 ppm at gas flow rate, temperature is under 570 ℃ the condition, is that 8 inches, length are that 12 inches particulate filter is simulated to diameter.As shown in Figure 4, cleaning pressure drop (being expressed as 0 grams per liter (g/l)) increases along with the increase of pit canal density (cpsi), and the pressure drop (representing with 6g/l) that loads behind the soot increases along with reducing of pit canal density.In addition, the difference of the pressure drop behind cleaning pressure drop and the loading soot increases along with reducing of pit canal density.Fig. 4 has shown that for pit canal density approximately less than the situation of 200cpsi, this kind effect is strong especially, and along with reducing of pit canal density, the pressure drop that loads behind the soot enlarges markedly.Therefore, in order low cleaning pressure drop to be provided and soot to be loaded steep pressure drop response, the present invention has considered to have the particulate filter of low pit canal density, and for example pit canal density is approximately less than 200cpsi, and for example pit canal density is approximately less than 150cpsi.In Fig. 4, along with the variation of pit canal density, wall thickness also changes, and makes the volume density constant of equal value (for example be 200/18 with 200/12cpsi/ mil) of different comparison filters.It will be appreciated by those skilled in the art that when comparing filter, sometimes it is important to keep volume density constant, this is because volume density can determine under the horizontal situation of given particulate loading, and the maximum filtering actuator temperature in the regenerative process increases.

Fig. 5 has shown similar effects, and Fig. 5 has shown at various pit canal density 150cpsi, 200cpsi, and under the condition of 250cpsi and 300cpsi, pressure drop is along with the analog data result of the variation relation of soot loading.In Fig. 5, it is 1400 meters at gas flow rate ³/ hour, temperature is under 500 ℃ the condition, to diameter be that 12 inches, length are that 8 inches, wall thickness are that 8 mils (1 mil=1/1000 inch), porosity ratio are 50%, mean pore sizes is that 19 microns particulate filter is simulated.As shown in Figure 5, for lower pit canal density, 200cpsi and 150cpsi, the degree that pressure drop increases along with the soot loading is higher.

Fig. 6 has shown that for 8 inches of various filter length 10 inches, 12 inches and 14 inches, pressure drop is along with the analog data result that soot loading (unit is a gram (g)) changes (is shown as curve 150/14/8; 150/14/10; 150/14/12; With 150/14/14, the length of last the numeral filter in the serial number wherein).In Fig. 6, it is 1400 meters at gas flow rate ³/ hour, temperature is under 500 ℃ the condition, to diameter be that 12 inches, wall thickness are that 14 mils, wall pore rate are 50%, mean pore sizes is that 19 microns, the particulate filter of 150cpsi are simulated.As shown in Figure 6, the slope of pressure drop-soot loading curve of filter (filter that for example has short filter length) with low length/diameter ratio is bigger.For example, the length/diameter ratio is that 8/12 (0.66) filter is about 70 seconds corresponding to air speed ^-1, its slope is about three times of slope that the length/diameter ratio is 14/12 (1.17) filter, and the corresponding air speed of the latter is about 40 seconds ^-1Therefore; In order to provide soot is loaded steep pressure drop response, the present invention has considered to have the particulate filter of lower length/diameter ratio, and for example the length/diameter ratio is approximately less than 1; For example the length/diameter ratio is approximately less than 0.85; Perhaps for example the length/diameter ratio is approximately less than 0.7, and corresponding to bigger air speed, for example air speed is approximately greater than 40 seconds ^-1, perhaps for example air speed approximately greater than 70 seconds ^-1

Fig. 7 A, 7B and 7C have shown that for various passage wall thickness 8 mils, 10 mils, 12 mils and 14 mils under various pit canal density 150cpsi (Fig. 7 A), 200cpsi (Fig. 7 B) and 300cpsi (Fig. 7 C) condition, the pressure drop response is to the sensitivity of soot loading.At Fig. 7 A, among 7B and the 7C, it is 1400 meters at gas flow rate ³/ hour, temperature is under 500 ℃ the condition, is that 12 inches, length are 8 inches to diameter, the wall pore rate is 50%, mean pore sizes is that 19 microns particulate filter is simulated.Shown in each figure; Shown in each the bar curve among the figure; The increase of wall thickness can cause the cleaning pressure drop of particulate filter to increase, and also can cause the increase of the pressure drop behind the loading soot of particulate filter, thereby the pressure drop that causes loading along with soot increases and has higher slope.But like Fig. 7 A, shown in 7B and the 7C, this kind is because the degree of the increase of the slope that the wall thickness increase causes is moderate.Therefore, no matter take which kind of pit canal density (cpsi), the benefit of the cleaning pressure drop that the maintenance of small wall thickness degree is low always surpasses the higher effect of slope that loads the pressure drop increase that causes along with soot.Therefore, in order to keep low cleaning pressure drop, the present invention has considered that passage wall thickness is for example approximately less than the particulate filter of 14 mils.

As if although the porous wall microstructure of particulate filter can not cause appreciable impact to the fluid-pressure drop that high soot loads (for example cake bed filtration stage) under the horizontal situation, the increase of the initial drop that the parameter of known wall pore rate, aperture and pore-size distribution and so on can cause to the filter efficiency of the cleaning pressure drop of filter and filter with owing to deep-bed filtration impacts.Therefore, such microstructure character can also be used for soot being loaded the particulate filter with steep pressure drop response at cake bed filtration stage.As discussed above, the present invention considers to utilize the various microstructure character of particulate filter to realize required low cleaning pressure drop, high filter efficiency, and the increase of initial drop reduces.Identical with the described situation of preamble, in order to confirm these microstructure character, have the structural design range of variables of the particulate filter of these required characteristics with analog data and laboratory data acquisition.

Fig. 8 A and 8B and 9A and 9B have shown the various combinations for pit canal density/wall thickness respectively, and promptly 200cpsi/12 mil, 200cpsi/18 mil and 275cpsi/12 mil clean pressure drop to the mean pore sizes of wall and the sensitivity of wall pore rate.In Fig. 8 A and 9A, be 427 kilograms/hour at gas flow rate, temperature is under 25 ℃ the condition, the particulate filter of 5.66 inches of diameters, 6 inches of length to be simulated.Shown in Fig. 8 A, porosity ratio be about 50% particulate filter the wall mean pore sizes approximately less than 13 microns situation under, the cleaning pressure drop enlarges markedly, and when the wall mean pore sizes was approximately greater than 13 microns, moderate reducing only took place in the cleaning pressure drop.Shown in Fig. 9 A, the cleaning pressure drop of particulate filter with about 15 microns wall mean pore sizes (MPS) is along with medium reducing takes place for the increase of wall pore rate.Therefore, show among the figure that the cleaning pressure drop is more insensitive to the increase of wall pore rate, but to the wall mean pore sizes to reduce (for example approximately less than 13 microns) comparatively sensitive.

Similarly, Fig. 8 B and 9B shown have various pit canal density/(that is, the 200cpsi/12 mil is corresponding to rhombus for the filter of wall thickness combination; The 200cpsi/18 mil is corresponding to square; The 275cpsi/12 mil is corresponding to triangle) result of the experiment test that carries out.As indicated above, be 427 kilograms/hour at gas flow rate, temperature is under 25 ℃ the condition, the filter of 5.66 inches of diameters, 6 inches of length to be tested.Above analog data is confirmed Fig. 8 B has shown that also the cleaning pressure drop is to the increase of wall pore rate more insensitive, and Fig. 9 B has shown that also the cleaning pressure drop reduces the comparison sensitivity to the wall mean pore sizes.

Result shown in Figure 10 A and 10B and 11A and the 11B has proved the sensitivity of initial (cleaning and filtering) filter clogging effect to wall mean pore sizes and wall pore rate.In Figure 10 A and 11A; At gas flow rate is that 15.59cfm (cubic feet/min), temperature are under 25 ℃ the condition, is that 275cpsi, wall thickness are that 12 mils (275/12), diameter are that 5.66 inches, length are that 6 inches filter is simulated to pit canal density.Shown in Figure 10 A, when the mean pore sizes of wall was reduced to about 14 microns from about 20 microns, the initial filter efficient that the wall pore rate is about 50% particulate filter increased to about 58% from about 34%.Shown in Figure 11 A, when the wall pore rate of filter increases to approximately 55% the time from about 48%, the initial filter efficient that mean pore sizes is about 17 microns particulate filter increases to about 45% from about 42%.Therefore, show among the figure that initial filter efficient is more insensitive to the increase of wall pore rate, but to the wall mean pore sizes reduce the comparison sensitivity, enlarge markedly along with reducing of wall mean pore sizes.

Similarly; Figure 10 B and 11B shown have various pit canal density/filter of wall thickness combination (is 275cpsi/12 mil (275/12, corresponding to square) and 200cpsi/12 mil (200/12; Corresponding to rhombus)) the experiment test result; The diameter of said filter is 5.66 inches, and length is 6 inches, is that 15.59cfm, temperature are to test under 25 ℃ the condition at gas flow rate.For analog data is confirmed; 275/12 curve among Figure 11 B shown that also initial filter efficient is comparatively insensitive to the increase of wall pore rate, and 275/12 curve among Figure 10 B has further shown initial filter efficient the wall mean pore sizes reduced the comparison sensitivity.

Figure 12 has shown that the wall pore rate is to because the analog data result of the influence of the initial back pressure pressure drop slope that deep-bed filtration causes.Shown in figure 12, be that 26.25cfm, temperature are under 25 ℃ the condition particulate filter to be simulated at gas flow rate, the diameter of said particulate filter is 2 inches; Length is 6 inches; Mean pore sizes is about 20 microns, contributes about 6% porosity ratio less than 10 microns hole, greater than the porosity ratio of 40 microns hole contributions 10.25%; Along with the wall pore rate increases to 54% from 48%, initial drop slope (on the y axle, recording) reduces.

Therefore; In order to make particulate filter realize required pressure drop and filter clogging effect; Exemplified embodiment of the present invention has considered to use the mean pore sizes of porous wall to be about the 13-20 micron, or to be about the structure of 13-16 micron; It can obtain higher filter clogging effect performance, can not make the cleaning pressure drop of filter enlarge markedly simultaneously.In addition, although the cleaning pressure drop is only along with moderate raising takes place in the increase of wall pore rate, bigger wall pore rate can also help to reduce because the high initial back pressure that deep-bed filtration causes.Therefore, the present invention also considered to use porous wall overall porosity approximately greater than 45% structure.Other illustrative embodiments of the present invention has also considered to use the overall porosity of porous wall to be about the particulate filter of 45-60%, to solve because the negative effect that the higher porosity level possibly cause to the volume density/thermal mass of filter.

Figure 13 has shown that cinclides directly distributes to because the analog data result of the influence of the initial back pressure pressure drop slope that causes of deep-bed filtration.Shown in figure 13, initial back pressure pressure drop is to comparatively sensitive less than the porosity ratio of 10 microns hole (through the aperture of mercury porosity ratio technical measurement) contribution by the aperture.As shown in the figure; Particulate filter is that 26.25cfm, temperature are to simulate under 25 ℃ the condition at gas flow rate, and the diameter of said filter is 2 inches, and length is 6 inches; Mean pore sizes is about 19 microns; Porosity ratio is 52%, and about (simultaneously, the aperture is reduced to about 9.6% greater than the porosity ratio of 40 microns hole contribution from about 10.68% 12% the time when the aperture increases to from about 2.15% less than the porosity ratio of 10 microns hole contribution; To keep pore-size distribution constant intermediate value is arranged), the slope of the initial drop in deep-bed filtration stage increases about 66%.Therefore; Through a kind of filtration device structure is provided, its pore-size distribution makes less than 10 microns hole contribution approximately less than 10% porosity ratio, for example approximately less than 6% porosity ratio; For example, has the increase that helps reduce initial drop in the deep-bed filtration stage approximately less than 2% porosity ratio.

Those of ordinary skills can understand, and only are exemplary with reference to the result of Fig. 4-13 demonstration and description and the geometry and the microstructure character of correspondence, can't constitute the scope of the present invention or claims and limit.For example; Get into the character of the fluid stream of said structure; For example the concentration of the pollutant in temperature, pressure, the fluid and/or other materials and flow velocity (the inflow system, flow through in system; And the flow velocity that flows out from system) also be to need the factor considered, so that select the geometry and the microstructure character of filter according to the present invention.Therefore; Those skilled in the art can understand; Particulate filter of the present invention and the method that is used for particulate filter regeneration can comprise multiple geometry and microstructure parameters; These parameters can obtain low cleaning pressure drop, at cake bed filtration stage the steep pressure drop that particulate loads responded, and in the low pressure drop response of steep bed filtration stage to the particulate loading.

Following examples have shown the model particulate filter; It has various filter parameter; Low cleaning pressure drop is provided under all gases flow conditions; The low pressure drop response (the shallow slope of for example pressure drop-soot loading curve) that soot is loaded in the deep-bed filtration stage, and in the high pressure drop response (the steep slope of for example pressure drop-soot loading curve) of cake bed filtration stage to the soot loading.

According to the present invention, at flow velocity (Q _Ref) be 1400 meters ³/ hour, temperature (T _Ref) be under 500 ℃ the exhaust gas conditions; Diameter is that 12 inches, length are that 8 inches, wall thickness are that 12 mils, pit canal density are that 200cpsi, wall pore rate are 45%, mean pore sizes be 19 microns, wherein less than the particulate filter of the porosity ratio of 10 microns hole contribution 10% have following pressure drop and pressure drop response: 1.67kPa (kPa) low cleaning pressure drop; Dark bed pressure drop under the soot loading environment of 0.05 grams per liter is 1.84kPa, is 2.57kPa in the cake bed pressure drop under the soot loading environment of 1 grams per liter (for the filter after regulating).

In addition; Be 3.4kPa/ (grams per liter soot) in the deep-bed filtration stage to the low pressure drop response (at the pressure drop response slope in deep-bed filtration stage) that the particulate of particulate filter loads, and it is 0.9kPa/ (grams per liter soot) that the steep pressure drop that the particulate of particulate filter is loaded at cake bed filtration stage responds (the pressure drop response slope of cake bed filtration stage).

Use and identical filter parameter mentioned above and exhaust gas parameters, difference is, in the pore-size distribution of filter, contributes 6% porosity ratio less than 10 microns holes, the low cleaning pressure drop of 1.61kPa, and the dark bed pressure drop under the 0.05 grams per liter condition is 1.75kPa.In addition; Be 2.8kPa/ (grams per liter soot) in the deep-bed filtration stage to the low pressure drop response (at the pressure drop response slope in deep-bed filtration stage) that the particulate of particulate filter loads, and it is 0.9kPa/ (grams per liter soot) that the steep pressure drop that the particulate of particulate filter is loaded at cake bed filtration stage responds (the pressure drop response slope of cake bed filtration stage).

Use and identical filter parameter mentioned above and exhaust gas parameters, difference is, in the pore-size distribution of filter, contributes 2% porosity ratio less than 10 microns holes, the low cleaning pressure drop of 1.55kPa, and the dark bed pressure drop under the 0.05 grams per liter condition is 1.66kPa.In addition; Be 2.2kPa/ (grams per liter soot) in the deep-bed filtration stage to the low pressure drop response (at the pressure drop response slope in deep-bed filtration stage) that the particulate of particulate filter loads, and it is 0.9kPa/ (grams per liter soot) that the steep pressure drop that the particulate of particulate filter is loaded at cake bed filtration stage responds (the pressure drop response slope of cake bed filtration stage).

But, use hereinafter described pantography and formula, can be from any flow velocity in groups and temperature conditions convergent-divergent required pressure drop response and relevant filter geometric properties and microstructure.Therefore, those of ordinary skills can utilize pantography hereinafter described to confirm filter, and this filter configuration becomes can realize low cleaning pressure drop, the pressure drop response slope that the deep-bed filtration stage is low, and the steep pressure drop response slope of cake bed filtration stage.

The definition of Eu-number Eu and reynolds number Re is following:

Eu = \frac{ΔP}{(ρ U_{f}^{} / 2)};

Re = \frac{{ρU}_{f} D}{μ}

Wherein Δ P representes the pressure drop on the filter, and ρ representes fluid (for example gas) density, and D representes the filter diameter, and μ representes fluid (for example gas) viscosity, U _fPresentation surface speed, can be by the flow velocity Q of fluid (for example gas) according to computes:

U_{f} = \frac{4 Q}{π D^{2}}

Eu-number of under experimental condition and reference condition, describing and Reynolds number scale are made (EU ₁, Re ₁) and (Eu _Ref, Re _Ref), therefore can use following relation, will be under the flow velocity of experiment and temperature conditions (Q ₁, T ₁) pressure drop that records zooms to reference condition (Q _Ref, T _Ref):

Load (SL)=0 for soot

Eu ₁Re ₁＝Eu _refRe _ref

For SL＞0

Eu ₁Re ₁SCF ₁＝Eu _refRe _ref?SCF _ref

Wherein SCF is Stokes-Ku Ning Durham (Stokes-Cunningham) factor correction, is the function of the Knudsen number Knp in particulate layer hole, and it defines as follows:

SCF＝1+Knp(1.257+0.4exp(-1.1/Knp))

The Knudsen number in particulate (for example soot) layer hole is defined as:

L wherein _MfpBe the gas mean free path, d _ParticulateBe the diameter of particulate (for example soot), S_vf is the solid fraction of particulate (for example soot) layer.

Other characteristics of particulate filter of the present invention can also change as required; Comprise the material that is used for said structure; The node configuration of passage (for example size, shape etc.); And/or get into the fluid stream of said structure character, the for example pollutant in temperature, pressure, the fluid and/or the concentration of other materials, and flow velocity (comprise the inflow system, in system, flow through and the flow velocity of outflow system).Those of ordinary skill can be understood; Various parameters according to the fluid stream that overall after-treatment system is operated and needs are handled; Various characteristics mentioned above and at least a portion of characteristic can be selected, to help to realize low cleaning pressure drop and the pressure drop response steep to the particulate loading.

But, based on content of the present invention, in general; The character how those skilled in the art can understand filter improves; The character of said filter comprises for example its how much and microstructure character, to realize required high-pass filter FE, low cleaning pressure drop; In the deep-bed filtration stage (if any) particulate is loaded low pressure drop response; And, in improvement, use convergent-divergent step mentioned above in the pressure drop response steep of cake bed filtration stage to the particulate loading, consider the various positive performance characteristics of constitutive property as herein described.

In addition, although each exemplary mode of execution of the present invention relates to the particulate filter that is used for from automobile exhaust gas, crossing leaching and soot particulate matter, the present invention includes the filter that can be used for various application and filter the wide range of various particulate matters.Exemplary application includes but not limited to for example be used for the filter of coal fired power generation station, petrol engine and static and non-static application.

From the purpose of this specification and appended claims, unless otherwise indicated, otherwise, the numerical value of all expression amount, percentage or ratio, and other the numerical value that uses in specification and claims all is interpreted as with term " about " and modifies.Therefore, only if opposite explanation is arranged, otherwise used numerical parameter is an approximate number in this specification and claims, can hope the desirable properties that realizes according to the present invention and changes.Bottom line, but be not the scope that is limited in claim for the application with doctrine of equivalents, each numerical parameter should and adopt general approximate number technology to make an explanation according to the significant figure that write down at least.

Though limiting the number range and the parameter of broad range of the present invention is approximate number, the numerical value in the specific embodiment is record as far as possible exactly.Yet any numerical value must contain some error that is caused by the standard deviation of finding in its mensuration process separately.In addition, all scopes of this paper announcement all are interpreted as the whole arbitrarily subrange that comprises in this scope.

It should be noted that to remove ciphertext and in so many words be confined to one to refer to thing, otherwise " one ", " a kind of " and " being somebody's turn to do " of the singulative that in this specification and accompanying claims, uses comprise the plural thing.In the present invention, " comprising " speech and phraseological modification thereof are intended to not have narrow limitation, thus to one the tabulation item citation be not to being substituted into or adding to the eliminating of other similar item in the Listed Items.

Be to be understood that; Though describe the present invention in detail with regard to some illustrative embodiments; But should think and the invention is not restricted to these illustrative embodiments; Under the prerequisite of the broad range of the present invention that does not deviate from appended claims and limited, can carry out various possible modifications to the mode of execution of enumerating.

Claims

1. particulate filter, it comprises:

Entry end, outlet end and a plurality of passage, said passage setting also is configured such that fluid flows from entry end towards outlet end,

Said passage is used for the porous wall of capturing particulates material structure and limits, and said porous wall has following character:

Cell densities is approximately less than 200cpsi,

Wall thickness is approximately less than 14 mils,

Mean pore sizes is about the 13-20 micron,

Overall porosity is approximately greater than 45%,

Pore-size distribution makes less than 10 microns hole contribution approximately less than 10% porosity ratio.

2. particulate filter as claimed in claim 1 is characterized in that said particulate filter has honeycomb body structure.

3. particulate filter as claimed in claim 2 is characterized in that, said porous wall structure is used for capturing soot.

4. particulate filter as claimed in claim 1 is characterized in that said cell densities is approximately less than 150cpsi.

5. particulate filter as claimed in claim 1 is characterized in that said overall porosity is about 45-60%.

6. particulate filter as claimed in claim 1 is characterized in that said mean pore sizes is about the 13-16 micron.

7. particulate filter as claimed in claim 1 is characterized in that, said pore-size distribution makes less than 10 microns hole contribution approximately less than 6% porosity ratio.

8. particulate filter as claimed in claim 1 is characterized in that, said pore-size distribution makes less than 10 microns hole contribution approximately less than 2% porosity ratio.

9. particulate filter as claimed in claim 1 is characterized in that, the length/diameter ratio of said particulate filter is approximately less than 1.

10. particulate filter as claimed in claim 1 is characterized in that, the length/diameter ratio of said particulate filter is approximately less than 0.85.

11. particulate filter as claimed in claim 1 is characterized in that, the length/diameter ratio of said particulate filter is approximately less than 0.7.

12. particulate filter as claimed in claim 1 is characterized in that, the length/diameter of said particulate filter compares corresponding to air speed approximately greater than 40 seconds ^-1

13. particulate filter as claimed in claim 1 is characterized in that, the length/diameter of said particulate filter compares corresponding to air speed approximately greater than 70 seconds ^-1

14. particulate filter as claimed in claim 1 is characterized in that, said a plurality of channels configuration become to be used for making that engine exhaust flows through.

15. particulate filter as claimed in claim 1 is characterized in that, said particulate filter is a diesel particulate filter.

16. particulate filter as claimed in claim 1 is characterized in that, said particulate filter comprises stupalith.

17. particulate filter as claimed in claim 16 is characterized in that, said particulate filter comprises steinheilite.

18. particulate filter as claimed in claim 16 is characterized in that, said particulate filter comprises silicon carbide.

19. a particulate filter, it comprises:

Said passage is used for the porous wall of capturing particulates material structure and limits,

It is that 500 ℃, rate of flow of fluid are 1400 meters that said particulate filter is configured such that in temperature ³/ hour condition under the fluid that flows through from said particulate filter have following character: from the entry end to the outlet end, have the low cleaning pressure drop that is less than or equal to 1.7 kPas approximately; In the deep-bed filtration stage; Particulate loading to particulate filter has low pressure drop response, is defined as slope and is less than or equal to 3.4kPa/ (g/L soot density) approximately, at cake bed filtration stage; Particulate loading to particulate filter has steep pressure drop response, is defined as slope approximately greater than 0.9kPa/ (g/L soot density).

20. particulate filter as claimed in claim 19 is characterized in that, said is approximately less than 2.75kPa/ (g/L soot density) in the deep-bed filtration stage to the low pressure drop response of the particulate loading of particulate filter.

21. particulate filter as claimed in claim 19 is characterized in that, said is approximately less than 2kPa/ (g/L soot density) in the deep-bed filtration stage to the low pressure drop response of the particulate loading of particulate filter.

22. particulate filter as claimed in claim 19 is characterized in that, said is approximately less than 1.5kPa/ (g/L soot density) in the deep-bed filtration stage to the low pressure drop response of the particulate loading of particulate filter.

23. particulate filter as claimed in claim 19 is characterized in that, said low cleaning pressure drop is under different EGTs and waste gas flow velocity, through multiply by Eu-number and reynolds' number calculates.

24. particulate filter as claimed in claim 19; It is characterized in that; The said low pressure drop response that the particulate of particulate filter is loaded in the deep-bed filtration stage and be under different EGTs and waste gas flow velocity to the steep pressure drop response that the particulate of particulate filter loads at cake bed filtration stage calculates through multiply by Eu-number, reynolds' number and Stokes-Ku Ning Durham correction factor.